Nucleocosmochronology

Nucleocosmochronology

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Nucleocosmochronology, also known as cosmochronology, is a relatively new technique used to determine timescales for astrophysical objects and events. This technique employs the abundances of heavy radioactive nuclides
Radionuclide
A radionuclide is an atom with an unstable nucleus, which is a nucleus characterized by excess energy available to be imparted either to a newly created radiation particle within the nucleus or to an atomic electron. The radionuclide, in this process, undergoes radioactive decay, and emits gamma...

 to calculate the age of formation of astronomical objects in a similar fashion to the dating of rocks in the field of geochronology
Geochronology
Geochronology is the science of determining the age of rocks, fossils, and sediments, within a certain degree of uncertainty inherent to the method used. A variety of dating methods are used by geologists to achieve this, and schemes of classification and terminology have been proposed...

.

Nucleocosmochronology has already been successfully employed to determine the age of the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

 ( billion years) and of the Galactic thin disk , among others. It has also been used to estimate the age of the Milky Way
Milky Way
The Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...

 itself, as exemplified by recent study of Cayrel's Star
Cayrel's Star
BPS CS31082-0001, named Cayrel's Star, is an old Population II star located in a distance of 4 kpc in the Galactic Halo. It belongs to the class of ultra-metal-poor stars , especially the very rare subclass of neutron-capture enhanced stars. It was discovered by Tim C...

 in the Galactic halo
Galactic halo
The term galactic halo is used to denote an extended, roughly spherical component of a galaxy, which extends beyond the main, visible component. It can refer to any of several distinct components which share these properties:* the galactic spheroid...

. Limiting factors in its precision are the quality of observations of faint stars, and perhaps more importantly, the uncertainty of the primordial abundances of r-process
R-process
The r-process is a nucleosynthesis process, likely occurring in core-collapse supernovae responsible for the creation of approximately half of the neutron-rich atomic nuclei that are heavier than iron. The process entails a succession of rapid neutron captures on seed nuclei, typically Ni-56,...

 elements.

See also

  • Astrochemistry
    Astrochemistry
    Astrochemistry is the study of the abundance and reactions of chemical elements and molecules in the universe, and their interaction with radiation. The discipline is an overlap of astronomy and chemistry. The word "astrochemistry" may be applied to both the Solar System and the interstellar medium...

  • Cayrel's Star (CS31082-001)
    Cayrel's Star
    BPS CS31082-0001, named Cayrel's Star, is an old Population II star located in a distance of 4 kpc in the Galactic Halo. It belongs to the class of ultra-metal-poor stars , especially the very rare subclass of neutron-capture enhanced stars. It was discovered by Tim C...

  • Metallicity
    Metallicity
    In astronomy and physical cosmology, the metallicity of an object is the proportion of its matter made up of chemical elements other than hydrogen and helium...

  • Nucleosynthesis
    Nucleosynthesis
    Nucleosynthesis is the process of creating new atomic nuclei from pre-existing nucleons . It is thought that the primordial nucleons themselves were formed from the quark–gluon plasma from the Big Bang as it cooled below two trillion degrees...

  • Radiometric dating
    Radiometric dating
    Radiometric dating is a technique used to date materials such as rocks, usually based on a comparison between the observed abundance of a naturally occurring radioactive isotope and its decay products, using known decay rates...

  • Stellar evolution
    Stellar evolution
    Stellar evolution is the process by which a star undergoes a sequence of radical changes during its lifetime. Depending on the mass of the star, this lifetime ranges from only a few million years to trillions of years .Stellar evolution is not studied by observing the life of a single...